六盘水煤田煤层气赋存特征及有利区评价

近5年来，六盘水煤田多个区块的煤层气试采开发取得了较大突破，但其煤层气聚集单元多、勘探开发条件差异大，整体评价该区煤层气赋存特征及预测综合有利区对本区煤层气开发决策至关重要。研究区有22个主要含煤向斜，即煤层气聚集单元，不同煤层气聚集单元上二叠统含煤岩系具有单煤层厚度薄、顶底板封盖性好、煤层含气量高、地应力较大、煤体结构偏差、低孔低渗、储层超压频繁的共性特征，但在煤层气资源丰度、资源量、煤层累计厚度、构造、埋深、煤阶、试采效果、勘探程度和地面条件等方面差异较大，根据各煤层单元的共性与差异性确定了煤层气综合开发评价的3个二级指标（资源条件、储集条件和开发基础条件）及对应的9个三级指标，采用多层次模糊数学方法对22个煤层气聚集单元进行了有利区优选排序，优选出5个建议优先开发的煤层气单元、9个适合接替开发的煤层气单元及8个远景煤层气开发单元。 

Occurrence characteristics and assessment of favorable areas of coalbed methane exploration in Liupanshui coalfield

Coalbed methane(CBM)development test has gotten significant progress in multiple blocks of Liupanshui coalfield during the last 5 years. There are many CBM accumulation units with different exploration and development conditions in the study area, so the overall evaluation of CBM occurrence characteristics and comprehensive prediction of favorable blocks are crucial for CBM development decisions in the area. The common features of different CBM accumulation units in Upper Permian coal-bearing formation is thin single seam, good cap rock of roof and floor, high gas content, high ground stress, poor coal structure, low porosity and permeability, generally high pressure coefficient, but larger differences in CBM resource abundance and resources, cumulative thickness of coal seam, structure, buried depth, coal rank, production test effect, exploration degree and ground conditions. After that, three second-order indices(resource condition, reservoir condition and developmental foundation condition)and their corresponding nine third-order indices for CBM comprehensive development assessment are established. The comprehensive evaluation and ranking result of 22 CBM accumulation units in the study area is determined by the fuzzy mathematics for favorable block selection. The results show that five CBM accumulation units are favorable blocks for priority development, nine CBM accumulation units are the more favorable areas recommended substituting development, and eight CBM accumulation units are the prospective areas.